Cannot revert blender to its default "Blender" interaction mode
Go to File->User Preferences.  In the Input tab, you can check the Show Splash checkmark on the bottom right of the window if you want the start up screen to come up each time.  In the Input tab, the first option will let you set the presets from Blender or 3Dsmax or Maya.  Finally, press "Save User Settings" to save what you did so that every time you start up blender, those same settings will be used.